Davis J Hal, Verdi Richard
U.S. Geological Survey, Northboro, MA 01532.
Ground Water. 2014 Sep-Oct;52(5):705-16. doi: 10.1111/gwat.12125. Epub 2013 Oct 18.
Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half.
斯普林克里克泉和瓦库拉泉是源自佛罗里达上层含水层的大型一级泉。水下的斯普林克里克泉位于一个河口，而瓦库拉泉位于内陆18公里处。从20世纪30年代至今，瓦库拉泉的流量持续增加。这种增加可能是由于海平面上升，这给水下的斯普林克里克泉带来了额外的压力水头，减少了其淡水流量，并增加了瓦库拉泉的流量。为了更好地理解这些泉之间的复杂关系，于2007年6月25日至2010年6月30日收集了流量和盐度数据。斯普林克里克泉的流量对降雨和海水入侵最为敏感，而瓦库拉泉的流量对降雨和斯普林克里克泉的流量最为敏感。发现这些泉的水流是相互连通的，并且在岩溶泉水流循环中由三个重复阶段组成：第一阶段发生在降雨较少的时期，其特征是海水回流到斯普林克里克泉的洞穴中。较高密度的海水阻止了淡水流动，导致斯普林克里克泉的等效淡水水头高于瓦库拉泉。被阻挡的淡水被分流到瓦库拉泉，其流量大约增加了一倍。第二阶段发生在暴雨导致小溪水流暂时升高，流向附近的落水洞，从而将斯普林克里克泉洞穴中的海水排出时。第三阶段发生在溪流恢复到基流之后。斯普林克里克泉洞穴的等效淡水水头低于瓦库拉泉，导致它们大量流出淡水，而瓦库拉泉的流量减少了约一半。
